apache/cassandra · error · InvalidRequestException

Unknown object type: '" + objectType + "'. Valid types are:

Error message

Unknown object type: '" + objectType + "'. Valid types are: " + Arrays.toString(ObjectType.values())

What it means

After resolving the keyspace, AbstractSchemaMetadataTable parses the first key component as an ObjectType (KEYSPACE, TABLE, etc.). If the component string is not a valid ObjectType name, InvalidRequestException is thrown listing the valid types. This indicates the queried object type token is malformed.

Source

Thrown at src/java/org/apache/cassandra/db/virtual/AbstractSchemaMetadataTable.java:223

    }

    @Override
    public DataSet data(DecoratedKey partitionKey)
    {
        SimpleDataSet result = new SimpleDataSet(metadata());

        ByteBuffer key = partitionKey.getKey();
        ByteBuffer[] components = ((CompositeType) metadata().partitionKeyType).split(key);
        String objectType = UTF8Type.instance.compose(components[0]);
        String keyspaceName = UTF8Type.instance.compose(components[1]);

        KeyspaceMetadata keyspace = Schema.instance.getKeyspaceMetadata(keyspaceName);
        if (keyspace == null)
            throw new InvalidRequestException("Unknown keyspace: '" + keyspaceName + '\'');

        ObjectType type = ObjectType.parse(objectType);
        if (type == null)
            throw new InvalidRequestException("Unknown object type: '" + objectType +
                                              "'. Valid types are: " + Arrays.toString(ObjectType.values()));

        switch (type)
        {
            case KEYSPACE:
                addKeyspaceRow(result, keyspace);
                break;
            case TABLE:
                for (TableMetadata table : keyspace.tables)
                    addTableRow(result, keyspace, table);
                break;
            case COLUMN:
                for (TableMetadata table : keyspace.tables)
                    for (ColumnMetadata column : table.columns())
                        addColumnRow(result, keyspace, table, column);
                break;
            case UDT:
                for (UserType udt : keyspace.types)

View on GitHub (pinned to 88fd0f6a0e)

Solutions

  1. Use one of the valid type strings printed in the error (match exact case, e.g. 'table', not 'tables')
  2. Prefer querying the dedicated system_schema tables (system_schema.tables, etc.) instead of constructing partition keys manually
  3. Upgrade tooling that emits object-type tokens to match this Cassandra version's ObjectType enum

Example fix

// before
SELECT * FROM system_schema_virtual.tables WHERE object_type = 'view';
// after
SELECT * FROM system_schema_virtual.tables WHERE object_type = 'table' AND keyspace_name = 'ks';
// or query system_schema.views directly
Defensive patterns

Strategy: validation

Validate before calling

Set<String> valid = Set.of("keyspace","table","type","function"); // per ObjectType enum
if (!valid.contains(objectType.toLowerCase())) throw new IllegalArgumentException("bad object type: " + objectType);

Try / catch

try { session.execute(q); } catch (InvalidRequestException e) { if (e.getMessage().startsWith("Unknown object type")) useValidTypeFromMessage(); else throw e; }

Prevention

When it happens

Trigger: SELECT from the schema-metadata virtual table with a partition key whose first component is a misspelled or unsupported object type, e.g. 'view' or 'index' where only enum values like keyspace/table/type/function are accepted.

Common situations: Hand-written partition-key queries against schema virtual tables using guessed type strings; tooling generating keys from internal metadata with different casing or vocabulary; version drift where newer object types don't exist in this release.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/5e8b325cadfaa7cc. Report an issue: GitHub.